Commit 4abead9e authored by Mark Haines's avatar Mark Haines
Browse files

Add c interface which wraps the cpp classes

parent 7cdde735
#ifndef AXOLOTL_HH_
#define AXOLOTL_HH_
#include <stddef.h>
#ifdef __cplusplus
extern "C" {
#endif
static const size_t AXOLOTL_MESSAGE_TYPE_PRE_KEY = 0;
static const size_t AXOLOTL_MESSAGE_TYPE_MESSAGE = 1;
struct AxolotlAccount;
struct AxolotlSession;
size_t axolotl_account_size();
size_t axolotl_session_size();
AxolotlAccount * axolotl_account(
void * memory
);
AxolotlSession * axolotl_session(
void * memory
);
size_t axolotl_error();
const char * axolotl_account_last_error(
AxolotlSession * account
);
const char * axolotl_session_last_error(
AxolotlSession * session
);
size_t axolotl_pickle_account_length(
AxolotlAccount * account
);
size_t axolotl_pickle_session_length(
AxolotlSession * session
);
size_t axolotl_pickle_account(
AxolotlAccount * account,
void const * key, size_t key_length,
void * pickled, size_t pickled_length
);
size_t axolotl_pickle_session(
AxolotlSession * session,
void const * key, size_t key_length,
void * pickled, size_t pickled_length
);
size_t axolotl_unpickle_account(
AxolotlAccount * account,
void const * key, size_t key_length,
void * pickled, size_t pickled_length
);
size_t axolotl_unpickle_session(
AxolotlSession * session,
void const * key, size_t key_length,
void * pickled, size_t pickled_length
);
size_t axolotl_create_account_random_length(
AxolotlAccount * account
);
size_t axolotl_create_account(
AxolotlAccount * account,
void const * random, size_t random_length
);
size_t axolotl_account_identity_keys_length(
AxolotlAccount * account
);
size_t axolotl_account_identity_keys(
AxolotlAccount * account,
void * identity_keys, size_t identity_key_length
);
size_t axolotl_account_one_time_keys_length(
AxolotlAccount * account
);
size_t axolotl_account_one_time_keys(
AxolotlAccount * account,
void * identity_keys, size_t identity_key_length
);
/* TODO: Add methods for marking keys as used, generating new keys, and
* tracking which keys have been uploaded to the central servers */
size_t axolotl_create_outbound_session_random_length(
AxolotlSession * session
);
size_t axolotl_create_outbound_session(
AxolotlSession * session,
AxolotlAccount * account,
void const * their_identity_key, size_t their_identity_key_length,
unsigned their_one_time_key_id,
void const * their_one_time_key, size_t their_one_time_key_length,
void const * random, size_t random_length
);
size_t axolotl_create_inbound_session(
AxolotlSession * session,
AxolotlAccount * account,
void * one_time_key_message, size_t message_length
);
size_t axolotl_matches_inbound_session(
AxolotlSession * session,
void * one_time_key_message, size_t message_length
);
size_t axolotl_encrypt_message_type(
AxolotlSession * session
);
size_t axolotl_encrypt_random_length(
AxolotlSession * session
);
size_t axolotl_encrypt_message_length(
AxolotlSession * session,
size_t plaintext_length
);
size_t axolotl_encrypt(
AxolotlSession * session,
void const * plaintext, size_t plaintext_length,
void const * random, size_t random_length,
void * message, size_t message_length
);
size_t axolotl_decrypt_max_plaintext_length(
AxolotlSession * session,
size_t message_type,
void * message, size_t message_length
);
size_t axolotl_decrypt(
AxolotlSession * session,
size_t message_type,
void * message, size_t message_length,
void * plaintext, size_t max_plaintext_length
);
#ifdef __cplusplus
}
#endif
#endif /* AXOLOTL_HH_ */
#include "axolotl/axolotl.hh"
#include "axolotl/session.hh"
#include "axolotl/account.hh"
#include "axolotl/base64.hh"
#include "axolotl/cipher.hh"
#include <new>
#include <cstring>
namespace {
static AxolotlAccount * to_c(axolotl::Account * account) {
return reinterpret_cast<AxolotlAccount *>(account);
}
static AxolotlSession * to_c(axolotl::Session * account) {
return reinterpret_cast<AxolotlSession *>(account);
}
static axolotl::Account * from_c(AxolotlAccount * account) {
return reinterpret_cast<axolotl::Account *>(account);
}
static axolotl::Session * from_c(AxolotlSession * account) {
return reinterpret_cast<axolotl::Session *>(account);
}
static std::uint8_t * from_c(void * bytes) {
return reinterpret_cast<std::uint8_t *>(bytes);
}
static std::uint8_t const * from_c(void const * bytes) {
return reinterpret_cast<std::uint8_t const *>(bytes);
}
static const std::uint8_t CIPHER_KDF_INFO[] = "Pickle";
static const axolotl::CipherAesSha256 PICKLE_CIPHER(
CIPHER_KDF_INFO, sizeof(CIPHER_KDF_INFO) -1
);
std::size_t enc_output_length(
size_t raw_length
) {
std::size_t length = PICKLE_CIPHER.encrypt_ciphertext_length(raw_length);
length += PICKLE_CIPHER.mac_length();
return axolotl::encode_base64_length(length);
}
std::uint8_t * enc_output_pos(
std::uint8_t * output,
size_t raw_length
) {
std::size_t length = PICKLE_CIPHER.encrypt_ciphertext_length(raw_length);
length += PICKLE_CIPHER.mac_length();
return output + axolotl::encode_base64_length(length) - length;
}
std::size_t enc_output(
std::uint8_t const * key, std::size_t key_length,
std::uint8_t * output, size_t raw_length
) {
std::size_t ciphertext_length = PICKLE_CIPHER.encrypt_ciphertext_length(
raw_length
);
std::size_t length = ciphertext_length + PICKLE_CIPHER.mac_length();
std::size_t base64_length = axolotl::encode_base64_length(length);
std::uint8_t * raw_output = output + base64_length - length;
length -= PICKLE_CIPHER.mac_length();
PICKLE_CIPHER.encrypt(
key, key_length,
raw_output, raw_length,
raw_output, ciphertext_length,
raw_output, length
);
axolotl::encode_base64(raw_output, length, output);
return raw_length;
}
std::size_t enc_input(
std::uint8_t const * key, std::size_t key_length,
std::uint8_t * input, size_t b64_length,
axolotl::ErrorCode & last_error
) {
std::size_t enc_length = axolotl::decode_base64_length(b64_length);
if (enc_length == std::size_t(-1)) {
last_error = axolotl::ErrorCode::INVALID_BASE64;
return std::size_t(-1);
}
axolotl::decode_base64(input, b64_length, input);
std::size_t raw_length = enc_length - PICKLE_CIPHER.mac_length();
std::size_t result = PICKLE_CIPHER.decrypt(
key, key_length,
input, enc_length,
input, raw_length,
input, raw_length
);
if (result == std::size_t(-1)) {
last_error = axolotl::ErrorCode::BAD_ACCOUNT_KEY;
}
return result;
}
std::size_t b64_output_length(
size_t raw_length
) {
return axolotl::encode_base64_length(raw_length);
}
std::uint8_t * b64_output_pos(
std::uint8_t * output,
size_t raw_length
) {
return output + axolotl::encode_base64_length(raw_length) - raw_length;
}
std::size_t b64_output(
std::uint8_t * output, size_t raw_length
) {
std::size_t base64_length = axolotl::encode_base64_length(raw_length);
std::uint8_t * raw_output = output + base64_length - raw_length;
axolotl::encode_base64(raw_output, raw_length, output);
return base64_length;
}
std::size_t b64_input(
std::uint8_t * input, size_t b64_length,
axolotl::ErrorCode & last_error
) {
std::size_t raw_length = axolotl::decode_base64_length(b64_length);
if (raw_length == std::size_t(-1)) {
last_error = axolotl::ErrorCode::INVALID_BASE64;
return std::size_t(-1);
}
axolotl::decode_base64(input, b64_length, input);
return raw_length;
}
const char * errors[9] {
"SUCCESS",
"NOT_ENOUGH_RANDOM",
"OUTPUT_BUFFER_TOO_SMALL",
"BAD_MESSAGE_VERSION",
"BAD_MESSAGE_FORMAT",
"BAD_MESSAGE_MAC",
"BAD_MESSAGE_KEY_ID",
"INVALID_BASE64",
"BAD_ACCOUNT_KEY",
};
} // namespace
extern "C" {
size_t axolotl_error() {
return std::size_t(-1);
}
const char * axolotl_account_last_error(
AxolotlSession * account
) {
unsigned error = unsigned(from_c(account)->last_error);
if (error < 9) {
return errors[error];
} else {
return "UNKNOWN_ERROR";
}
}
const char * axolotl_session_last_error(
AxolotlSession * session
) {
unsigned error = unsigned(from_c(session)->last_error);
if (error < 9) {
return errors[error];
} else {
return "UNKNOWN_ERROR";
}
}
size_t axolotl_account_size() {
return sizeof(axolotl::Account);
}
size_t axolotl_session_size() {
return sizeof(axolotl::Session);
}
AxolotlAccount * axolotl_account(
void * memory
) {
return to_c(new(memory) axolotl::Account());
}
AxolotlSession * axolotl_session(
void * memory
) {
return to_c(new(memory) axolotl::Session());
}
size_t axolotl_pickle_account_length(
AxolotlAccount * account
) {
return enc_output_length(pickle_length(*from_c(account)));
}
size_t axolotl_pickle_session_length(
AxolotlSession * session
) {
return enc_output_length(pickle_length(*from_c(session)));
}
size_t axolotl_pickle_account(
AxolotlAccount * account,
void const * key, size_t key_length,
void * pickled, size_t pickled_length
) {
axolotl::Account & object = *from_c(account);
std::size_t raw_length = pickle_length(object);
if (pickled_length < enc_output_length(raw_length)) {
object.last_error = axolotl::ErrorCode::OUTPUT_BUFFER_TOO_SMALL;
return size_t(-1);
}
pickle(enc_output_pos(from_c(pickled), raw_length), object);
return enc_output(from_c(key), key_length, from_c(pickled), raw_length);
}
size_t axolotl_pickle_session(
AxolotlSession * session,
void const * key, size_t key_length,
void * pickled, size_t pickled_length
) {
axolotl::Session & object = *from_c(session);
std::size_t raw_length = pickle_length(object);
if (pickled_length < enc_output_length(raw_length)) {
object.last_error = axolotl::ErrorCode::OUTPUT_BUFFER_TOO_SMALL;
return size_t(-1);
}
pickle(enc_output_pos(from_c(pickled), raw_length), object);
return enc_output(from_c(key), key_length, from_c(pickled), raw_length);
}
size_t axolotl_unpickle_account(
AxolotlAccount * account,
void const * key, size_t key_length,
void * pickled, size_t pickled_length
) {
axolotl::Account & object = *from_c(account);
std::uint8_t * const pos = from_c(pickled);
std::size_t raw_length = enc_input(
from_c(key), key_length, pos, pickled_length, object.last_error
);
if (raw_length == std::size_t(-1)) {
return std::size_t(-1);
}
std::uint8_t * const end = pos + raw_length;
unpickle(pos, end, object);
return pickled_length;
}
size_t axolotl_unpickle_session(
AxolotlSession * session,
void const * key, size_t key_length,
void * pickled, size_t pickled_length
) {
axolotl::Session & object = *from_c(session);
std::uint8_t * const pos = from_c(pickled);
std::size_t raw_length = enc_input(
from_c(key), key_length, pos, pickled_length, object.last_error
);
if (raw_length == std::size_t(-1)) {
return std::size_t(-1);
}
std::uint8_t * const end = pos + raw_length;
unpickle(pos, end, object);
return pickled_length;
}
size_t axolotl_create_account_random_length(
AxolotlAccount * account
) {
return from_c(account)->new_account_random_length();
}
size_t axolotl_create_account(
AxolotlAccount * account,
void const * random, size_t random_length
) {
return from_c(account)->new_account(from_c(random), random_length);
}
namespace {
static const std::size_t OUTPUT_KEY_LENGTH = 2 + 10 + 2 +
axolotl::encode_base64_length(32) + 3;
void output_key(
axolotl::LocalKey const & key,
std::uint8_t sep,
std::uint8_t * output
) {
output[0] = sep;
output[1] = '[';
std::memset(output + 2, ' ', 10);
uint32_t value = key.id;
uint8_t * number = output + 11;
*number = '0' + value % 10;
value /= 10;
while (value) {
*(--number) = '0' + value % 10;
value /= 10;
}
output[12] = ',';
output[13] = '"';
axolotl::encode_base64(key.key.public_key, 32, output + 14);
output[OUTPUT_KEY_LENGTH - 3] = '"';
output[OUTPUT_KEY_LENGTH - 2] = ']';
output[OUTPUT_KEY_LENGTH - 1] = '\n';
}
} // namespace
size_t axolotl_account_identity_keys_length(
AxolotlAccount * account
) {
return OUTPUT_KEY_LENGTH * 2 + 1;
}
size_t axolotl_account_identity_keys(
AxolotlAccount * account,
void * identity_keys, size_t identity_key_length
) {
std::size_t length = OUTPUT_KEY_LENGTH * 2 + 1;
if (identity_key_length < length) {
from_c(account)->last_error =
axolotl::ErrorCode::OUTPUT_BUFFER_TOO_SMALL;
return size_t(-1);
}
std::uint8_t * output = from_c(identity_keys);
output_key(from_c(account)->identity_key, '[', output);
output += OUTPUT_KEY_LENGTH;
output += OUTPUT_KEY_LENGTH;
output[0] = ']';
return length;
}
size_t axolotl_account_one_time_keys_length(
AxolotlAccount * account
) {
size_t count = from_c(account)->one_time_keys.size();
return OUTPUT_KEY_LENGTH * (count + 1) + 1;
}
size_t axolotl_account_one_time_keys(
AxolotlAccount * account,
void * identity_keys, size_t identity_key_length
) {
std::size_t length = axolotl_account_one_time_keys_length(account);
if (identity_key_length < length) {
from_c(account)->last_error =
axolotl::ErrorCode::OUTPUT_BUFFER_TOO_SMALL;
return size_t(-1);
}
std::uint8_t * output = from_c(identity_keys);
output_key(from_c(account)->last_resort_one_time_key, '[', output);
output += OUTPUT_KEY_LENGTH;
for (auto const & key : from_c(account)->one_time_keys) {
output_key(key, ',', output);
output += OUTPUT_KEY_LENGTH;
}
output[0] = ']';
return length;
}
size_t axolotl_create_outbound_session(
AxolotlSession * session,
AxolotlAccount * account,
void const * their_identity_key, size_t their_identity_key_length,
unsigned their_one_time_key_id,
void const * their_one_time_key, size_t their_one_time_key_length,
void const * random, size_t random_length
) {
if (axolotl::decode_base64_length(their_identity_key_length) != 32
|| axolotl::decode_base64_length(their_one_time_key_length) != 32
) {
from_c(session)->last_error = axolotl::ErrorCode::INVALID_BASE64;
return std::size_t(-1);
}
axolotl::Curve25519PublicKey identity_key;
axolotl::RemoteKey one_time_key;
axolotl::decode_base64(
from_c(their_identity_key), their_identity_key_length,
identity_key.public_key
);
one_time_key.id = their_one_time_key_id;
axolotl::decode_base64(
from_c(their_one_time_key), their_one_time_key_length,
one_time_key.key.public_key
);
return from_c(session)->new_outbound_session(
*from_c(account), identity_key, one_time_key,
from_c(random), random_length
);
}
size_t axolotl_create_inbound_session(
AxolotlSession * session,
AxolotlAccount * account,
void * one_time_key_message, size_t message_length
) {
std::size_t raw_length = b64_input(
from_c(one_time_key_message), message_length, from_c(session)->last_error
);
if (raw_length == std::size_t(-1)) {
return std::size_t(-1);
}
return from_c(session)->new_inbound_session(
*from_c(account), from_c(one_time_key_message), raw_length
);
}
size_t axolotl_matches_inbound_session(
AxolotlSession * session,
void * one_time_key_message, size_t message_length
) {
std::size_t raw_length = b64_input(
from_c(one_time_key_message), message_length, from_c(session)->last_error
);
if (raw_length == std::size_t(-1)) {
return std::size_t(-1);
}
bool matches = from_c(session)->matches_inbound_session(
from_c(one_time_key_message), raw_length
);
return matches ? 1 : 0;